The future trend of the field of liquid crystal display (LCD) is to make the product thinner, lighter, and with higher definition. Therefore, when connecting and aligning each component during the manufacturing process, the degree of flatness and accuracy thereof is very important. Thus, stability, precision, and correction action of the manufacturing equipment will directly affect the yield rate and quality of the manufactured product. Currently, a pressure-sensitive paper is generally used to test the parallelism of the laminating apparatus.
The pressure-sensitive paper is a component used to detect pressure value, pressure distribution, and pressure uniformity. After applying pressure to the pressure-sensitive paper, the color of the pressure-sensitive paper changes; the higher the pressure is, the darker the color becomes. Thereby, the pressure value, pressure distribution and pressure uniformity may be detected.
The color-changing principle of the pressure-sensitive paper is described below. When pressure is applied to the pressure-sensitive paper, breaking fine color particles inside the pressure-sensitive paper, the broken color particles will react with color developing agent material to produce color. The fine color particles are specially designed to detect various pressure values and pressure distribution through molecular control technology for fine particles. The higher the pressure applied to the pressure-sensitive paper is, the more color particles inside the pressure-sensitive paper are broken, thereby presenting darker color. The pressure-sensitive papers with different pressure-measuring range may be selected according to the value of the pressure applied. For instance: micro pressure (0.5˜2 kgf/cm2); extreme low pressure (2˜6 kgf/cm2); super low pressure (5˜25 kgf/cm2); low pressure (25˜100 kgf/cm2); medium pressure (100˜500 kgf/cm2); high pressure (500˜1300 kgf/cm2); super high pressure (1300˜3000 kgf/cm2).
Hence, the pressure-sensitive paper may be used in, for example, the field of ceramic tile industry, spring unit design, point welding, machining, music instrument manufacturing, furniture industry, LCD module, aerospace industry, tire industry, and medical clinical biologic analysis.
The pressure-sensitive paper is capable of showing the pressure value applied thereto by presenting different color brightness. The pressure-sensitive paper is also capable of measuring the pressure value between junction surfaces attached together, wherein the pressure measurement range is within 0.5 kgf/cm2˜3000 kgf/cm2. Therefore, product quality may be significantly enhanced, and reduce the extra cost caused by multiple adjustment or modification when relying on only human judgment.
A power module is required for a liquid crystal panel inside a liquid crystal display, in order to supply electric power and control signal thereto. The voltage is applied to liquid crystal unit of the liquid crystal panel to control rotation of liquid crystal, in order to achieve the goal of brightness variation. The liquid crystal panel and the circuit board of the power module are connected to each other through a flexible circuit board. Since the flexible circuit board is extremely thin, and driver IC and electronic component may be embedded thereto; therefore, when laminating the flexible circuit board onto the liquid crystal panel and the power module, the lamination force and uniformity of that force are both significant process parameter. In order to improve uniformity of the lamination force, upper and lower lamination surfaces of the lamination equipment should be parallel to each other to ensure uniformity of the force. Hence, the parallelism between the upper and lower lamination surfaces of the lamination equipment are constantly measured and monitored.
FIG. 1 is a structural view illustrating a parallelism measuring system 1 according to the prior art. The parallelism measuring system 1 according to the prior art includes a measured unit 10, an assisting unit 11, a reference unit 12, and a pressure-sensitive paper 13. Wherein, lower surface of the measured unit 10 is a measured flat surface 101, and an upper surface of the measured unit 10 is attached to the assisting unit 11. The assisting unit 11 is used to adjust the inclination angle of the measured unit 10, and to allow the measured unit 10 to move upwards and downwards. The upper surface of the reference unit 12 is a flat reference surface 121; therefore, the reference surface 121 is used as the reference plane for parallelism measurement.
Wherein, the pressure-sensitive paper 13 is disposed above the reference surface 121 of the reference unit 12. When the assisting unit 11 is used to allow the measured unit 10 to vertically move downwards and apply pressure onto the reference unit 12, the pressure-sensitive paper 13 is held between the measured surface 101 and the reference surface 121, and thereby the pressure-sensitive paper 13, according to foregoing color-changing principle, presents different color brightness based on the pressure value applied thereof. Hence, manufacturers may determine about the force uniformity of the pressure applied from the measured surface 101 onto the reference surface 121, and then, by using the assisting unit 11 to adjust the inclination angle of the measured unit 10, make the measured surface 101 of the measured unit 10 and the reference surface 121 of the reference unit 12 parallel to each other.
The pressure-sensitive paper is a kind of one-time use consumable material of high cost. Further, relying on only color brightness changes may not achieve the goal of effective digitization. Therefore, it is important to develop an alternative method capable of measuring stably, being used multiple times, and digitalizing the measured result.